Checkpointing mods for IOC::read(). Doesn't build yet.

src/Utilities.cpp

@@ -0,0 +1,106 @@
+#include "Utilities.h"
+#include "IOCoordinator.h"
+
+namespace storagemanager
+{
+
+
+ScopedReadLock::ScopedReadLock(IOCoordinator *i, const std::string &k) : ioc(i), key(k)
+{
+    lock();
+}
+ScopedReadLock::~ScopedReadLock()
+{
+    unlock();
+}
+
+void ScopedReadLock::lock()
+{
+    assert(!locked);
+    ioc->readLock(key);
+    locked = true;
+}
+
+void ScopedReadLock::unlock()
+{
+    if (locked)
+    {
+        ioc->readUnlock(key);
+        locked = false;
+    }
+}
+
+ScopedWriteLock::ScopedWriteLock(IOCoordinator *i, const std::string &k) : ioc(i), key(k)
+{
+    lock();
+}
+ScopedWriteLock::~ScopedWriteLock()
+{
+    unlock();
+}
+
+void ScopedWriteLock::lock()
+{
+    assert(!locked);
+    ioc->writeLock(key);
+    locked = true;
+}
+
+void ScopedWriteLock::unlock()
+{
+    if (locked)
+    {
+        ioc->writeUnlock(key);
+        locked = false;
+    }
+}
+
+ScopedCloser::ScopedCloser(int f) : fd(f) { }
+ScopedCloser::~ScopedCloser() { 
+    int s_errno = errno;
+    ::close(fd);
+    errno = s_errno; 
+}
+
+
+
+struct SharedCloser
+{
+    public: 
+        SharedCloser(int f);
+        SharedCloser(const SharedCloser &);
+        ~SharedCloser();
+    
+    private:
+        struct CtrlBlock
+        {
+            int fd;
+            uint refCount;
+        };
+        
+        CtrlBlock *block;
+};
+    
+SharedCloser::SharedCloser(int f)
+{ 
+    block = new CtrlBlock();
+    block->fd = f;
+    block->refCount = 1;
+}
+
+SharedCloser(const SharedCloser &s) : block(s.block)
+{
+    block->refCount++;
+}
+
+SharedCloser::~SharedCloser()
+{
+    block->refCount--;
+    if (block->refCount == 0)
+    {
+        ::close(block->fd);
+        delete block;
+    }
+}
+    
+}